The one uncovered at Liscahane on the outskirts of Millstreet, County Cork, seems to have been neither finished nor properly begun. When construction workers broke ground for a local-authority housing development in 2003, they found a small subterranean chamber that appears to have been abandoned mid-build, sometime in the early medieval period, before anyone ever used it for anything at all.

The chamber itself is modest, measuring 2.5 metres long, 0.85 metres wide, and just over a metre high, roofed by three large lintels laid across its drystone walls. What is peculiar is the absence of any formal entrance. Whoever built it never got that far; access was only possible through the open, unfinished south-western corner. A large rectangular pit found nearby, at right angles to the south-eastern corner and roughly 1.9 metres away, told a similarly incomplete story. It had been back-filled shortly after it was dug, with large quantities of stone suggesting that an attempt had been made to construct stone facing inside it, an attempt that was evidently given up. Excavation of two trenches, each around 30 metres long, to the west and south of the chamber found no trace of any enclosing structure around the site, which leaves the souterrain curiously isolated, with no obvious parent settlement detectable nearby. The excavator, reporting in 2006, concluded that the structure was most likely abandoned before it was ever completed, leaving behind what amounts to an early medieval building site, preserved for thirteen centuries beneath a Cork housing estate.